1. Field of the Invention
This invention is generally directed to earthworking and earth boring equipment and more specifically to an implement for injecting chemicals to subsurface areas in order to treat the soil or the roots of plants or trees and thereafter seal the opening in the earth's surface to prevent the escape of chemical fumes to atmosphere. The implement of the present invention is designed to be conveniently mounted to conventional farm equipment including tractors so as to be powered by the hydraulic system of such equipment. The implement includes a ground penetrating bit which supports a fluid injector nozzle adjacent the penetrating end thereof and which cooperates with the fluid injector nozzle to prevent the nozzle from being obstructed as the nozzle is introduced to subsurface areas. Chemicals are introduced through the injector nozzle in predetermined or measured quantities after the chemicals have been introduced into a metering tank. A source of pressure is utilized to discharge the chemicals from the metering tank so that the chemicals are introduced under high pressure through the injector. Following the injection of a chemical to a given location, the bit and nozzle are withdrawn while a tamping mechanism is simultaneously operated so as to close the opening in the earth's surface so as to prevent the escape of any chemical gases to atmosphere.
The injection implement of the present invention may be utilized to inject various types of chemicals including various plant growth stimulants, fertilizers or herbicides and poisons as may be required in a given location.
2. History of the Related Art
It is a well known practice to introduce various chemicals to subsurface areas in order to effect the growth conditions of soils. In some instances, chemicals are added at depths of between a foot to three feet in order to destroy potentially damaging weed growth or plant growth which would otherwise interfere with the growth of agricultural crops. In other instances, the chemicals may be supplied to destroy parasitic or other animal life which may be threatening to a particular agricultural crop. On the other hand, it may be necessary to supply plant growth nutrients at relatively deep locations in order to support the growth of trees and other plants having deep root systems. The introduction of chemicals to subsurface areas is also preferred in instances where the chemical could adversely effect surrounding areas if the chemical were to be applied topically and therefore capable of being introduced into the ground water run off at a given location. By injecting the chemicals at a depth where the chemical will not mix with surface waters, chemicals are contained in the area where they will have the most effect and are prevented from effecting other environmental conditions until after such time as they have become sufficiently delute and non-toxic. One example of the injection of volatile chemical soil fumigants to subsurface areas is disclosed in U.S. Pat. No. 3,964,405 to Haglund et al. In this patent, the control of deeply rooted perennial weeds is accomplished by injecting fumigants at depths of between 14-24 inches below ground level at given rates of application.
There have been a number of different structures designed and developed to introduce chemicals to subsurface areas. The simplest and least complex type of injectors are designed to be portable and carried by a laborer in the field. Such units include a ground probe which is connected to a tank which may be pressurized by operation of a pump mechanism connected directly to the tank. In the field, the worker inserts the probe to a desired depth and thereafter opens the valve to permit the injection of a portion of the chemical retained within the pressurized tank. Such units have limited applicability in that they may only be used in well tilled areas where the penetration of the ground engaging wand is relatively simple. Further, such a system does not provide for insuring a specific measured quantity of chemical being introduced at each subsurface location and therefore the effective control of the amount of chemical is not possible. Further, the amount of chemical being dispensed is limited and the total effectiveness of such systems are directly dependent on the individual skill and strength of the worker in the field. Such systems may also be hazardous to individuals as the individual is directly exposed to the chemicals and the chemical injection site and thereby may be exposed to chemical fumes emanating from both the injector, spilled chemicals and chemicals introduced into the earth's surface.
In order to overcome the deficiencies of portable subsurface injectors, there have been various structures designed to be mechanically operated and which are utilized to introduce a chemical below the earth's surface. In some types of equipment, a bore is first made within the earth's surface after which a chemical is introduced into the bore. With this type of equipment, the chemical is exposed to atmosphere and fumes are allowed to emanate from the bore in the earth. Further, such systems are not efficient in that they require a significant amount of time in order to place the chemical at given subsurface areas. Other types of equipment include self-motorized vehicles which carry ground penetrating nozzles. One such self-motorized unit which is not utilized to inject gas but is used to detect subsurface gas in the soil is disclosed in U.S. Pat. No. 3,084,553 to Cullinan et al. Such equipment is prohibitively expensive for the conventional farmer in that a totally self-contained system must be purchased which system is only useful for the given purpose of subsurface soil testing or chemical injection. In addition, there are other problems which are inherent in many motorized injector systems. Often, the penetrating bit and chemical injecting nozzle are formed of the same element. In such instances, the injection openings from the bit may become clogged during repeated usage thereby preventing the effective injection of chemicals to a given location.
In U.S. Pat. No. 4,637,328 to Topham et al., a planting mechanism is disclosed which utilizes a pair of soil penetrating members for first depositing a quantity of seed at a specific predetermined depth and a fertilizer material at a given depth. Unfortunately, such equipment is not designed for deep subsurface penetration and is designed to be mechanically operated to relatively shallow depths where very little resistance is met by the injector nozzles. Such a system would not be operative at substantial depths including one to two feet below the surface.
Other more complicated types of subsurface injectors have also been designed. One example is disclosed in U.S. Pat. No. 2,789,522 to Barton. This apparatus is an extremely bulky piece of equipment which is trailered across a given area and which is provided with pumps for operating an injector mechanism. As with other prior art mechanical injectors, the structure is prohibitively costly and difficult to maneuver.